Electric safety system for railways.



No. 756,957. v PATENTED APR. 12, 1904. J. HANNA & 0. s. GILMAN.

ELECTRIC SAFETY SYSTEM FOR RAILWAYS.

APPLIGATION FILED MAY 7, 1902.

no MODEL.

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' UNITED STATEs Patented April 12, 1904.

PATENT @FFIQE.

ELECTRIC SAFETY SYSTEM FOR HAILWAYS.

SPECIFICATION forming part of Letters Patent :No. 756,957, dated April 12, 1904.

Application filed May '7, 1902.

To all whom, it may concern.-

Be it known that we, J AooB HANNA and CHARLES S. GILMAN, citizens of the United States, residing at Rivera, in the county of Los Angeles and State of California, have in vented a new and useful Electric Safety System for Railways, of which the following is a specification.

Our invention relates to a system of automatic train control and signaling, and has for its object to provide means for avoiding collisions between trains.

Another object is to provide means whereby the brakes of a train may be setand the train stopped by persons other than those of the train, thus making it possible to positively stop a train when it is impossible to signal the train or when the operators of the train have failed to act according to signals or instructions.

Another object is to provide a means for automatically signaling the engineer when the brakes are being set by causes not under his control, as before mentioned.

Another object is to provide a means for antomatically operating asignal at certain points on the road when the train is near those points.

Another object isto provide means'whereby trains controlled by our system may be allowed to approach each otherfor instance, when two trains are to meet and pass each other at a station--this means also being under control of persons other than those on the train. 7

Another object is to provide means whereby our system may be adapted to prevent either head-on collisions or rearend collisions.

Other objects-such as simplicity, economy of construction, reliability, and effectiveness of operation-are attained, which will be brought out in the following description.

Figure I is a view showing the arrangement of our system. Two cars are shown approaching a station and the electric switchis out of normal position, thereby breaking the main conductor to allow the cars to approach each other. Fig. II is a view showing a connection of a motor to an air-valve. Fig. III is a view showing a modified form of a portion of our system.

Serial No. 106,364. (No model.)

1 designates the ordinary rails of a track.

2 is a conductor insulated from the track, lying parallel with the track.

3 is a car having a trolley 4, which contacts with the conductor 2.

5 represents a brake-shoe, 6 an air-reservoir, 7 a brake-cylinder, 8 a train-pipe, and 9 an air-valve, of an air-brake apparatus carried by the car 3. Valve 9 is a rotary valve-that is, it is adapted to permit or out 01f the passage of air by its rotation, said valve being, for example, an ordinary plug-valve with an airway transversely through the plug, communicating in one position of the valve with ports on each side of the valve and in another position shutting off communication between such ports. The valve 9 may have a threaded stem 10. Revolubly mounted on the stem is a gear 11.

12 is an electric motor having an elongated driving-pinion 13 extending from its shaft. The pinion'lS meshes with the gear 11.

14c is a pipe for carrying exhaust-air from the valve 9 to the whistle 15.

The motor 12 is connected to the trolley 4 by a wire-16, while a wire 17 connects themotor with the track-rail 1 or ground.

18 is a battery.

19 is a pole-changing switch. It will be seen that when two cars are on the same track a circuit is formed through the conductor 2, trolley l, through switch 19,wire l6, and motor 12, then through wire 17 and switch 19 to the axle and wheel of the car, and thence to the rails 1 or ground and the similar electric equipment of the other car, and the strength of the current passing through the circuit will depend upon the strength of the batteries and also upon the resistance in the circuit, which resistance will depend upon the distance between the cars.

20 is an electric bell of the ordinary type which operates by causing a rapid make and break of the circuit, thus energizing and deenergizing its magnet, andis connected in the circuit above described and which may belocated adjacent a road-crossing 21.

22 is a switch for the conductor 2 trolled by a lever 23.

24: is a switch provided with contacts conand is connected by wire for connecting the conductor 2 and rail 1 and is controlled by a lever 25. In Fig. I the switch is shown as open. By moving the lever 25 toward the track the switch may be closed.

The levers 23 and 25 may be located at a station 26. The switch 24 may be made to control a considerable length of track by connecting therewith a local battery 27, which may be of any requisite strength to control a definite length of track.

The operation of the system is as follows: When two cars equipped as described come near enough together on the track to allow the batteries 18 to overcome the resistance in the circuit, the motors 12 are operated. The motors are of low power, and each motor is revolved by a current generated by batteries 18. The initial revolutions of a motor rotate the gear 11 and cause it to travel along the stem without rotating the valve-stem 10, thereby allowing the motor to attain momentum before it receives the resistance of the valve; but as soon as the gear engages the shoulder 1O the stem 10 is caused to rotate and then allows air to escape from the valve 9 at each revolution. When air is allowed to escape from the train-pipe 8, the brake 5 is applied to the wheel. The construction and operation of air-brake apparatus is well known and is therefore only shown diagrammatically.

The rotating action given to the valve causes a gradual escape of air step by step from the train-pipe, and thus gradually reduces the speed of the train until it stops. The air exhausted from the valve 9 is carried through the pipe 14: to the whistle 15 and warns the engineer that the brakes are being applied.

The batteries 18 may be constructed to produce a current sufficiently strong to operate the motors when trains come within a certain distance of each other-for instance, within half a mileand it is obvious that the apparatuses on each car operate coincidentally, thus bringing each train safely to a stop before a collision occurs.

When a car approaches the bell 20 at the crossing, the resistance in the circuit becomes sufficiently low to allow saidbell to ring, thus giving warning at the crossing of the approach of a train. When the bell rings, it causes a rapid succession of makes and breaks in the circuit and operates as an interrupter to the circuit, and thus the motor 12 does not operate to set the brakes. yond the bell the resistance in the circuit increases until the strength of the battery is not sufficient to overcome it, and thereupon the bell ceases to ring. If desired, other translating devices may be employed instead of a bell-for instance, a visual signal.

When two trains on the same track are to meet at a station, the switch 22 may be opened by a station official. This breaks the circuit As the car passes beand allows the trains to approach each other without the before-described automatic setting of the brakes. One train may be switched to a side track to allow the other to pass, after which the switch 22 should be closed, so that the circuit of the system will be reestablished. When a train has left a station and the operator thereafter receives orders to hold the train and it is impossible for him to signal thetrain, he may close the switch 2 1, and if the train has not passed beyond the effective circuit of battery 27 the current therefrom will cause the brakes to be set on the train, and further complications, and perhaps accidents, may thus be avoided. This switch is also useful in stopping trains at a station in cases where the engineer has carried the train by the station when it should be stopped, having failed either to observe or act upon the signals telling him to stop, as the station. official or other person having access to the lever may throw the switch 24 and stop the train so long as it is within the controllable limit.

The system may be made to prevent rearend collisions by simply throwing the switch 19. For instance, when a train stops on the road it is customary to send back a flagman for a considerable distance to stop any train that may be following. This procedure may be done away with by throwing the switch 19 to make the polarity conform to the poles of the battery on, the following train, which will cause the oncoming train to stop within a safe distance. Even when a fiagman is sent back sometimes the following train is so near that he does not have time to get a sufficient distance back to stop it in time and a rear-end collision occurs. Again, accidents have occured when the engineer of the oncoming train failed to see the flag or hear the torpedo. The switch 19 is especially useful'to avoid accidents on such occasions.

All trains running in the same direction on the track may have their switches 19 set alike to avoid head-on collisions, and rear-end collisions may be guarded against, as explained, by throwing the switch 19 as occasion requires.

The engineer may open the switch 19, and thus place the brakes under his exclusive control when it is desired to do so for instance, in the event of the rail 2 becoming accidentally connected with the ground.

Fig. III shows another form of connections. 30 is an electric generator connected to the motor 12 by wires 31 and 32. 33 is a solenoid for operating a switclr 3 1. The solenoid 33 is in the before-described track-circuit, and when the resistance in that circuit is lowered, as before explained, the solenoid throws the switch 3 1 and causes the motor 12 to be operated by the generator 30. The advantage of this form is that the batteries 18 may be regulated for a given distance of track without affecting the strength of current which opcrates the motor 12. The generator 30 may be the one usually employed on the train for lighting purposes.

We have termed the braking apparatus air-brakes; but it is evident that steambrakes, vacuum-brakes, or other forms of brakes may be controlled by our system as well. If desired, generators may be employed instead of the batteries shown. If an alternating current is employed, alternating generators may be substituted for the batteries shown. Other mechanisms than the motor for operating the valve may also be employed without evading the scope of our invention as defined in the claims.

If desired, the switch 19 may be locked and the key under the control of the conductor.

In using the word car in the specification and claims we include a locomotive or selfpropelling car or any other vehicle adapted to travel on a track.

It is obvious that many other variations and changes in the construction, arrangement in the mechanism, and electric connections may be made in the herein-described embodiment without departing from the spirit of our invention.

What we claim, and desire to secure by Letters Patent of the United States, is

1. An electric circuit comprising a trackrail conductor constituting one side of the circuit, an insulated normally closed conductor constituting the other side of the circuit and extending along the track, a car, an air-brake for said car, an air-valve therefor, an electric motor connected to operate said circuit and adapted to operate said air-valve to repeatedly open and close the same, and electric generating means on the car for energizing said circuit.

2. An electric circuit comprising a trackrail conductor forming one side of the circuit, an insulated normally closed conductor constituting the other side of thecircuit and extending along the track, a plurality of cars, air-brakes for said cars, air-valves for said brakes, electric motors on the cars connected to the circuits of the respective cars and connected to operate said air-valves to repeatedly open and close the same, and electric generating means on each car of such strength that when the cars approach sufficiently to decrease the resistance of said circuit to a definite amount, said motor will operate said valve to set the air-brakes on each car.

3. An electric circuit comprising a track forming one side of the circuit, and an insulated normally closed and continuous conductor forming the other side of the circuit and extending along the track, a car on the track, air-brakes on said car, a rotary valve controlling said air-brake, and an electric motor carried by said car to rotate said valve to alternately open and close the same, said means being connected to said circuit and controlled thereby, the resistance of said circuit being normally sufiicient to prevent said motor from being operated. 4:. An electric circuit, a car, air-brakes on said car, a valve connected to the air-brake system, the stem of said valve being threaded and having a shoulder thereon, a gear revolubly mounted on the threaded portion of said stem, a motor, the driving-shaft of said motor having an elongated pinion which meshes with said gear, a battery in said circuit to drive said motor, the resistance of said circuit being normally suflicient to prevent said motor from being operated.

5. A car, an air-brake for said car, a rotary air-valve for said brake, adapted upon continnous rotation to repeatedly open and close air communication therethrough, an electric motor operating said air-valve, an electric circuit, an energizing-circuit for said motor comprising a track-rail conductor and a continuous normally closed insulated conductor extending along the track, and means for interrupting said insulated conductor at a fixed point along the track to cause operation of the brakes from such fixed point.

6. An electric circuit comprising a track forming one side of the circuit, and an insulated normally closed and continuous conductor forming the other side of the circuit and extending along the track, a car on the track,

air-brakes on said car, a rotary valve controlling said air-brake, and an electric motor carried by said car to rotate said valve to alternately open and close the means, said means being connected to said circuit and controlled thereby, the resistance of said circuit being normally suflicient to prevent said motor from being operated, means for interrupting said 'insulated conductor at a fixed point along the track to cause operation of the brakes from such fixed point.

In testimony whereof we have signed our names, in the presence of two subscribing witnesses', at Rivera, in the county of Los Angeles and State of California, this 30th day of April, 1902.

' JACOB HANNA. CHARLES S. GILMAN.

Witnesses:

H. H. Wnsr, J. J. MULREIN.

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